[julia-users] Re: Never use Containers of abstract types? Aways Union with containers of subtypes, or use containers of Typed Parameterized containers?

[Lyndon White]

On Thursday, 11 June 2015 21:26:25 UTC+8, andrew cooke wrote:
>
>
> i don't know of any docs that justify this, but i would assume that Union 
> and Number would have very similar performance.
>
>
You would be wrong.
Union and {T<:Number} have similar performance.
Number performed 1000x worse.

For several reasons {T<:Number} is better, inclusing more sane error 
messages, less having to type out all subtypes etc.